improve debug output for error class

Author: rmosolgo

lib/graphql/invalid_null_error.rb

@@ -28,5 +28,23 @@ def to_h
     def parent_error?
       false
     end
+
+    class << self
+      attr_accessor :parent_class
+
+      def subclass_for(parent_class)
+        subclass = Class.new(self)
+        subclass.parent_class = parent_class
+        subclass
+      end
+
+      def inspect
+        if name.nil? && parent_class.respond_to?(:mutation) && (mutation = parent_class.mutation)
+          "#{mutation.inspect}::#{parent_class.graphql_name}::InvalidNullError"
+        else
+          super
+        end
+      end
+    end
   end
 end

lib/graphql/schema/object.rb

@@ -74,7 +74,7 @@ class << self
         # Set up a type-specific invalid null error to use when this object's non-null fields wrongly return `nil`.
         # It should help with debugging and bug tracker integrations.
         def inherited(child_class)
-          child_class.const_set(:InvalidNullError, Class.new(GraphQL::InvalidNullError))
+          child_class.const_set(:InvalidNullError, GraphQL::InvalidNullError.subclass_for(child_class))
           super
         end
 

spec/graphql/schema/mutation_spec.rb

@@ -118,7 +118,11 @@
       query_str = "mutation { returnInvalidNull { int } }"
       response = Jazz::Schema.execute(query_str)
       assert_equal ["Cannot return null for non-nullable field ReturnInvalidNullPayload.int"], response["errors"].map { |e| e["message"] }
-      assert_instance_of Jazz::ReturnInvalidNull.payload_type::InvalidNullError, response.query.context.errors.first
+      if TESTING_INTERPRETER
+        error = response.query.context.errors.first
+        assert_instance_of Jazz::ReturnInvalidNull.payload_type::InvalidNullError, error
+        assert_equal "Jazz::ReturnInvalidNull::ReturnInvalidNullPayload::InvalidNullError", error.class.inspect
+      end
     end
   end